The related patent, U.S. Pat. No. 5,114,163, of which this is a continuation-in-part, includes an embodiment illustrated in FIG. 8 for applications in which the shafts of the operating devices, such as pumps or turbines, are subject to greater axial shifts than those which would normally be expected. The design of that embodiment utilizes a thrust bearing to move a rotationally stationary split holder in conjunction with the axial movement of the shaft. That portion of the specification relating to the embodiment of FIG. 8 and other relevant portions of U.S. Pat. No. 5,114,163 are incorporated by reference herein where appropriate.
The FIG. 8 embodiment referenced in parent U.S. Pat. No. 5,114,163 by and large is able to withstand axial displacements of small proportions, on the order of 1/2 to 1 inch. However, any axial displacements greater than these would be hampered by the obstruction of the housing against the split holder member, which has only a limited degree of freedom in the axial direction before the seal formed by the O-ring disposed between the split holder member and the housing fails. Alternatively, the radially extending shoulder portion of the split holder will impinge on the radially extending wall of the housing.
Thus, what is necessary is a split mechanical face seal which can withstand much greater proportional axial displacements, up to 6 inches, without sacrificing the sealing characteristics of the split seal elements.